After days of pressure from anxious airline customers and concerned members of Congress, President Trump on Wednesday announced the grounding of Boeing’s 737 Max 8 aircraft — a stark reversal of the Federal Aviation Administration’s previous determination that the planes were safe enough to fly despite recent crashes in Indonesia and Ethiopia. The announcement came well after many other countries had grounded the aircraft.

According to the Federal Aviation Administration, its decision was based solely on its evolving understanding of the evidence. But critics have suggested that the delay in joining the international consensus may have been the result, at least in part, of the close relationship that Boeing, a major political force in Washington and a large government contractor, has with American officials.

Boeing receives more federal money than any corporation other than Lockheed Martin, its main competitor in the defense contractor industry. Boeing took in over $23 billion in contracts from the government in the 2017 fiscal year — near its annual average. (Just this fall, the company won a $9.2 billion contract to make a new generation of jets for the Air Force.)

Senator Elizabeth Warren publicly questioned whether the government had “put lives at risk” to protect Boeing’s bottom line. She and a bipartisan group of her colleagues requested congressional hearings to investigate.

Boeing certainly has strong ties to politicians in Washington. Senator Richard Blumenthal, Democrat of Connecticut, reacting to the delay, called Boeing “one of the 800-pound gorillas around here.” Last year, the company spent about $15 million on lobbying. And its employees, political action committees and other affiliated groups have donated more than $8.4 million in campaign contributions since 2016, giving to Democrats and Republicans in equal measure.

But while Boeing’s lobbying efforts may seem relatively unobjectionable — most in the mainstream acknowledge that businesses, like citizens, have a right to petition their government — the idea that a government contractor can have a hand in political donations has historically raised more serious concerns. In 1940, Congress passed a law barring individuals and firms from making federal campaign contributions while they negotiate or perform federal contracts. The intent was to prevent companies from trying to bribe politicians for lucrative deals and to prevent lawmakers from extorting money from companies with business before the government.